Phonograph records and molding compositions



Patented Nov. 4, 1952 PHONOGRAPH RECORDSAND MOLDING- COMPOSITIONS JosephW. Ayers, Easton, Pau, asls'ignjor" to Agrashell lncl, acorporatioif ofDelaware 1.8 Claims; 1 invention. relates to phonograph records ofnovel. properties and to molding compositions from which such recordsare produced; As to the latter, it more particularly relates to filled,resin-base moltling coinpositions capable ofIproduci'n'g; liigli gradesound reproducingyrecords ofi the flexible" or so-c'all'ed non-breakabletype;

At the present time, most ofthe' phonograph records produced are of? therigid, breakable shellac basa type. These records are cheap to produce.because of the; low cost of shellac and because. such. recordsordinarilycontain apbr'oxi-- mately 70%. by weight of cheap-fillers Flexiblerecordsmanufactured fronrsynthetic esin's, such" as vinyl resins. havereplaced iii part shellac base: records because of. their superiordurability; resistance. to breakage. non-inflamniabil'i'ty and other.desirable properties; The-extension of use '01:? vinyl base-recordshas.- been lim'ited and? retarded because of a'number of. adverse"factors incl'udihgtliei'r higher. costdile-tothe highen price paid" forvinyl. resins" than. normally; paid. for she1lac;.th'e?greater expense.connected with the molding of flawless. recordsand the practicalnecessity for compounding. the fl'exib'le records-from unext'en'd'edi,or unfilIedlIvinyl'. resins;

The ultimate. object oflthelprlesent vention is to provide. flexible.soundi-reproducin; or: phone graph records having desirable, qualitiesof reproducibility, long playing I ife, a miliiimum ofintierferencezfrom surface noises and records having. mechanieal':vpropfer ness rigidity and. resistance. to frac wide. range. of.temperatures;

intermediate. object is: to prov-i .enciesiii' hot cl'imateswhichlwarpin may occur if the records have been subjected t accidental1116' over" Application June 25,1948}. SeliaINO. 35,282

ample-.2: pia-stieize arid" a iimitezijorsmaii q ti'ty of any one or anumber of c meow-ids or' In my copending' application; Serial" Number7881647, filed- November 28; 1947, nowiiPatent' Na.

particle size' ligno' 'cellulose" fillers; plasticitersand.otheringredientsincluding el'astomers, meme cants and" coloringagent's. These products have taining' the same.

commercially desirable profierties; the molding composition being":easily compressed of'moldeci and" the finished records being excellentto freedom from interferencefrom suriaejenoises; reproducibility, long;playing life and resistariee' to fracture; g Y

The described highly filled retards require" so" much blasticiz'er forimparting desired pressing qualities that they may: not meet the inostrigid commercial requirements as to co new". A more limited object of"the present invention is to reduce the" cold flow" properties of these"plans ticized, highly'filled, vinyl base records; I

Phonogr'a'pli record in ding compositions p'ri marilytontempiatezi by'the present invention are) composed of a; vinyl resin base} a"substantial amount of a verv'fi'r'iely dividedHalifidighd-cllulosefiller, of which walnut shellfio'ui'iisanex:

materials found by theapolic ant' to reduee the cold flow of records"iiijotiiiced therefrom. Such compounds are precipitated calciumsilicate.

recipitatedsilica; aluminum hydrate, and reir'i-' forcing clays: Thesecompounds or" m terials may be referred" to as stiffening? agents and toaccomplish this: function: they; so r s'ingly; must be very" infiarticle' size', that is tliey must not have amaximum average"rial-tide di ameter greater than sniicroiis and: prefefably a diameter"in the range"- off 011 micron. Complete freedom from particles larger"than about 45 microns is desirable view of the noise act'eristic's whichordinarily would be iiiniafted t0 the records roduced fromeomoos'i'tions con- The" amount of stifienifie" agent required depends,of ourse; one; numb r of obvious factors; as the" nature of the resinbase" and of" the extende as well as the proficitions' thereof em loyed,but iii addition it d'e} pends upon tlie particular stiffening-- agent"In general it may be stated. h wever; that the amount Of the stifienihg'ageflt never need, be

,m'ore'th'an 20% by voliilne. Usueny; 10 byvolume of: the least emcientof til stilfe ning agents is sufiic'ierit to r'educ'etliecoldflow of therecords produced" from the molding composition to a value withincommercially desirable limits. Somewhat less than 1 by volume of themoreefiicient stiffening. a fintsis adequate.

The invention contemplates molding composi tions and recordscontaining-any suitable vinyl resinbase, a number ofsald: bases" being:defined .in the literature; A: preferred vinyl resin base 1 is oneobtained by the cold polymerization 'of a vention are hard, dense,non-absorbent, non

fibrous, natural vegetable shell materials containing at least 45% byweight of combined pentosans, hexosans and lignins. They are preferablyemployed in amounts of from 35% to 60% by weight, but amounts as low as20% can be used to advantage in the compositions. terials contemplatedinclude endocarps as the shells of English walnuts;-black walnuts,pecans, Brazil nuts,cocoanutsandthelike; also the pits of apricots,olives, dates, peaches and thelikeand also certainhard, dense,non-fibrous barks of a number of trees. The ligno-cellulose extenderused in the composition must be of very fine particle size to obtainacceptable results, i. .e., the particles should all be smaller than30microns and at least 90% of the same should be smaller than 25microns. When in this fine condition, 40% by volume may be added to thecomposition without perceptiblyv increasing the surface noise level ofthe records produced from it, or to a degree as high as thatof the bestprior filled commercial. records. The extender contributes dimensionalstability, greater faithfulness of reproduction, increased wearresistance, improved processing features and alowering of the cost ofthe composition. i

lThemolding. compositions. of the present invention containing largeamounts of the, lignocellulose extender may be plasticized by theaddition of the desired amount of any of the known plasticizers, suchfor example as phthalic esters, chlorinated diph'enyl derivatives,tricresyl derivatives, halogenated naphthalene derivatives, lycol estersand'linear high molecular weight polyester resins prepared by thereaction of a dibasic acid The mawith a dihydric aliphaticv alcoholhaving plasticizing properties. 7 i

The molding compositions and records of the test, strips are supportedupon two knife edges three inches apart and a load of 1000 g. is placedin the middle and acrossthe strip. The weighted strip is then placed inan oven heated to 100 F.

and held there for one hour after which the load is removed from thestrip andthe strip is withdrawn from the oven. After a rest period ofhi:

teen minutes, the strip is tested for permanent distortion or curvatureby placin the ends of the test strip on a straight line and measuringthe distance between'this line and thecenter of the strip, the amount ofdistortion being reported in millimeters. Strips which show, on testing,a distortion or curvature of from 20 to 30 millimeters are considered tohave a high cold flow or to respond poorly to the cold flow test. Recordstrips showing a curvature of 4 millimeters or less are considered toexhibit excellent resistance to cold flow. Compositions testing not morethan 5 millimetersmeetthe most rigid commercial requirements. 1

Molding compositions of the present invention are illustrated in thefollowing examples:

- Example 1 1 Parts by weight Vinyl chloride-acetate resin Leadste'arate 1 Cai'nauba wax .5 Ligno-cellulose extender 35.43 Precipitatedcalcium silicate 7.76 Plasticizer 4.85 Dioctylphthalate 1.40 Color 1Wetting. agent .25

- on gat rs ei enstates exhibited; a

A composition similar to. lithe, above. in which.

none of the ligno-celluloseextender was replaced by' the precipitated.calciu n silicate" exhibited on tests. cold flow of. about 18millimeters.

In the foregoing example the meant oflligno- I cellulose" extender andalsp thev amount of precip itated calcium silicateare substantially lessthan in Example-'1. On test this composition exhibited a cold flow ofonly 2 millimeters; H j v A composition having proportions the same asabove in which noneof the ligno cellulose extender was replacedprecipitated calcium silicate exhibitedacold ilowof abou t'liimillimeters.

The moderate amount of precipitated silicon dioxide stifiens r Parts byweight Vinyl chloride-acetate resin Lead stearate l Carnauba wax .5 HLigno cellulose extender H 36.91 Dioctyl-phthalate 1 1.40 Plasticizer 14.35 Aluminum hydrate 1.5 Color 1 the compound to a remarkable Thealuminum hydrate; employed in this example, though present in a verysmall amount", is most effective as a stiffening agent and reduces thecold flow to an acceptable degree. In other compositions, largeramounts. may be required, as up to 5%.

The incorporation of the stiffening agents in the. compositions of thepresent invention as illustrated in the foregoing examples do not renderthe records produced therefrom brittle or mechanically weak, nor do theyincrease the noise level.

Record compositions containing reinforcing clays asstiffening agentshave been found effective-in reducing the cold flow, but they are not assatisfactory as those containing the stiffening agents of the foregoingexamples, for this agent ordinarily has an adverse effect upon thesurface noise of the phonograph records containing it.

The molding compositions of the invention may; be compounded inconventional equipment and in the conventional manner. However, thevery'flne particle size stiffening agent such as precipitated calciumsilicate and precipitated silicon dioxide are very difficult to dispersein resins, and therefore in compounding them, it is desirable to preparethem first in the resin base and then to add the resulting homogeneousmixture in required amounts to the other ingredients of the formula asthey are mixed together.

The compositions after being worked into a homogeneous mass at asuitable elevated temperature such as about 270 C. may be out a numberof times with a doctor blade and formed into biscuits in conventionalmanner. Thereafterthe biscuits may be molded or pressed at temperaturesin the neighborhood of 230 F. or higher and under a pressure of from1500 to 4000'pounds per square inch depending upon the typeyand size ofthe record to be produced. Steam heating for a period of a few secondsat a stamper temperature of 270 F. is usually sufficient. after whichcool Water is applied to the die for thirty seconds or more dependingupon the: temperature of the cooling water used. These pressingconditions and; thepressing cycle are well within industrialrequirements.

The molded records do not contain entrapped air: bubbles. and hence thepercentage of imperfeet and rejected records is much less than whenordinary vinylite compositions are ressed. The flash from the pressingoperation is rippled and can be removed easily by hand, which advantageis" in strong contrast tothe tough, horny flash formed when vinylitealone is pressed. The scrap and trimmings from the pressing operation;may be reused without difficulty, which again is in contrast with theproblems of recovering pure vinylite scrap.

The Present invention, which has heretofore beengdisclosed as beingapplicable primarily to the production of vinyl base records and recordcompositions, also contemplates in its broader aspects the production ofmolding compositions and molded products having bases of other resinsdefinable as phonograph record resin base materials, These bases ingeneral may be defined further as those resins having a modulus ofelasticity not greater than 6 and a compressive strength not greaterthan 19,000. Within this definition there may be mentioned the followingresins and resin-like molding compositions hereinafter referred tocollectively as resinous molding materials":

Acrylat'e Nylon Styrene Vinyl Cellulose nitrate Ethyl celluloseCellulose acetate Cellulose butyrate As tothe manner of performance ofthe herein disclosed stiffening agents, it can be said merely I thatthey change the rheological properties of the hereindescribed flexibleor non-rigid resin compositions. Just why these agents reduce theplastic flow of the compositions of records under the conditions of thecold flow test is not understood, for the many other compounds andsubtion is not limited to the specific details herein,

1 given but that it extends to all equivalent mate-- rial and procedureswhich will occur to those skilled in the art upon consideration of theclaims appended hereto. The amounts of the components specified in theclaims are by volume.

I claim: I. Molding compositions capable of producing coldflow-resistant molded products composed of a moldable masscontaining aresinous molding material having a modulus of elasticity not greaterthan 6 and a compressive strength not greater than 19,000, said. massnot having by itself the property of producing cold flow-resistant'molded products, in combination with a finely divided ligno-cellulosefiller the particles of which are not more than 30 microns in diameter,and

about 1 to 10 of a stiffening agent selected from the group consistingof precipitated calcium silicate, precipitated silica, aluminum hydrate,

, and reinforcing clays, the said agent having a maximum averageparticle diameter of not greater than 5 microns.

2. Molding compositions composed of a phonograph record vinyl resin baseand a finely divided ligno-cellulose. filler the particles of which arenot more than 30 microns in diameter, said base having its capability ofproducing cold flow-re.

sistant molded records enhanced by the addition 6." of about 1 to 10% ofa stiffening agent selected 1 "from the group consisting of precipitatedcalcium silicate, precipitated silica, aluminum hydrate,

and reinforcing clays, the said agent having a I maximum averageparticle diameter of not greater than 5 microns.

3. Molding compositions composed of a resin- 4 ous molding materialhaving a modulus of elasticity not greater than 6 and a compressivestrength not greater than 19,000 incombination with a ligno-cellulosefiller, the particles of which are not more than 30 microns in diameter,and having its capability of producing cold flowresistant molded recordsenhanced by the addition of from about 1 to about 10% ofaluminumhydrate, as a stiffening agent, the said agent having a maximumaverage particle diameter of not greater than microns.

4. A cold flow-resistant phonograph record having a cold flow ratingbelow 29 mm. and composed of a mixture of a resinous molding materialhaving a modulus of elasticity not greater than 6 and a, compressivestrength not greater than 19,000, a finely divided ligno-cellulosefiller the particles of which are not more than 30 microns in diameterand a plasticizer and containing in its structure about 1 to 10% of astiffening agent selected from the group consisting of precipitatedcalcium silicate, precipitated silica, aluminum hydrate, and reinforcingclays, the said agent having a maximum average particle diameter of notgreater than 5 microns, said mixture if molded without said agent havinga property of producing records of cold flow resistance of a rating ofnot less than 20 mm.

5. A cold flow-resistant phonograph record having a cold flow ratingbelow 20 mm. and composed of a vinyl resin, a ligno-cellulose filler theparticles of which are not more than microns in diameter and containingin its structure about 1 to 10% of a stiffening agent selected from thegroup consisting of precipitated calcium silicate, precipitated silica,aluminum hydrate, and reinforcing clays, the said agent having a maximumaverage particle diameter of not greater than 5 microns, said mixture ifmolded without said agent having a property of producing records of coldflow resistance of a rating of not less than 20 mm.

6. A cold flow-resistant phonograph record composed of a vinyl resin anda ligno-cellulose filler, the particles of which are not more than 30microns in diameter and containing in its structure from about 1 toabout 5% aluminum hydrate as a stiffening agent, the said agent having amaximum average particle diameter of not greater than 5 microns.

7. A phonograph record molding composition capable of producing moldedproducts of a low cold flow rating below 20 mm. composed of a vinylresin base, a finely divided ligno-cellulose filler of less than 30micron particle size, a plasticizer and about 1 to 10% of a cold flowinhibiting agent selected from the group consisting of precipitatedcalcium silicate, precipitated silica, aluminum hydrate, and reinforcingclays, the said agent having a maximum average particle diameter ofone-tenth micron, said compositions without said agent being capable ofproducing molded products only of a high cold flow rating of not lessthan 20 mm.

8. A phonograph record molding composition composed of a vinyl resinbase, a finely divided ligno-cellulose filler the particles of which arenot more than 30 microns in diameter, a plasticizer and about 1 to 10%of aluminum hydrate having a maximum average particle diameter of notgreater than five microns, said aluminum hydrate being present in anamount'which imparts cold flow resistance to said composition.

9. A phonograph record molding composition composed of a vinyl resinbase, a finely divided ligno-cellulose filler of less than 30 micronparticle size, a plasticizer and about 1 to 10% aluminum hydrate havinga maximum. average particle diameter of one-tenth micron, said aluminumhydrate being present in an amount which imparts cold fiow resistance tosaid composition.

10. A phonograph record molding composition capable of producing moldedproducts. of a low cold flow rating below 20 mm. composed of a 8 vinylresin base, a finely divided ligno-cellulose filler containing at least45% of combined pentosans, hexosans and lignins the particles of i whichfiller are less than 30 microns in size, a plasticizer and about 1 to10% of a cold flow inhibiting agent selected from the group consistingof precipitated calcium silicate, precipitated silica, aluminum hydrate,and reinforcing clays, th said agent having a maximum average particlediameter of not greater than five microns, said composition without saidagent being capable of producing molded products only of a high coldflow rating of not less than 20 mm.

11. A phonograph record molding composition capable of producing moldedproducts of a low cold fiow rating below 20 mm. composed of a vinylresin base, a finely divided ligno-cellulose filler containing at least45% of combined pentosans, hexosans and lignins, the particles of whichare not more than 30 microns in diameter and of which are finer than 25microns, a plasticizer and about 1 to 10% of a cold flow inhibitingagent selected from the group consisting of precipitated calciumsilicate, precipitated silica, aluminum hydrate and reinforcing clays,the said agent having a maximum average particle diameter of not greaterthan five microns, said composition without said agent being capable ofproducing molded products only of a high cold flow rating of not lessthan 20 mm.

12. A phonograph record molding composition composed of a vinyl resinbase, a finely divided ligno-cellulose filler containing at least 45% ofcombined pentosans, hexosans and lignins, the particles of which are notmore than 30 microns in diameter and 90% of which are finer than 25microns, a plasticizer and about 1 to 10% aluminum hydrate having amaximum average particle diameter of not greater than five microns, saidaluminum hydrate being present in an amount which imparts cold flowresistance to said composition.

13. The process of reducing cold flow properties of molding compositionscontaining resinous molding materials having a modulus of elasticity notgreater than 6, a compressive strength not greater than 19,000 andundesirable Warping tendencies after beingmolded and also containing afinely divided ligno-cellulose the particles of which are not more than30 microns in diameter, which consists of incorporating in suchcomposition before molding from about 1 to 10% of a stiffening agentselected from the group consisting of precipitated calcium silicate,precipitated silica, aluminum hydrate, and reinforcing clays, the saidagent havin a maximum average particle diameterof not greater than 5microns.

14. The process of imparting higher cold flow resistance to phonographrecords producible from plasticized, ligno-cellulosefilled, vinyl resinbase, molding compositions of low cold flow-resistant properties, saidfiller being composed of particle sizes not larger than 30 microns,consisting of incorporating into said molding composition about 1 to 10%of a member of the group consisting of precipitated calcium silicate,precipitated silica, aluminum hydrate, and reinforcing clays, the saidcompounds having a maximum average particle diameter of not greater thanfive microns.

15. The process of imparting cold flow resistance to phonograph recordsproducible from plasticized, vinyl resin base, molding compositionsfilled with ligno-cellulose material the particles of which are not morethan 30 microns in diameter, consisting of incorporating into said 9molding composition about 1 to 10% of aluminum hydrate, the saidcompound having a maximum average particle diameter of not greater thanfive microns.

16-. The process of impartingcold flow resistance to phonograph recordsproducible from plasticized, vinyl resin base, molding compositionsfilled with ligno-cellulose material the particles of which are not morethan 30 microns in diameter, consisting of incorporating into saidmolding composition about 1 to 10% of aluminum hydrate, the saidcompound having a maximum average particle diameter of one-tenth micron.

17. A vinyl resin base, phonograph record, moldin composition consistingof a ligno-cellulosic filler the particles of which are not more than'30 microns in diameter, a plasticizer, said composition having hotplastic flow capable of being molded into records at a temperature of270 stamper temperature at a pressure not in excess of 4000 pounds persquare inch, the said records having a cold flow of not more than 5millimeters imparted by the presence of about 1 to of a stifiening agentselected from the group consisting of precipitated calcium silicate,precipitated silica, aluminum hydrate, and reinforcing clays, said agenthavinga maximum average particle diameter of not greater than 5 microns.

silicate having a maximum average particle diameter of not greater than5 microns.

JOSEPH W. AYERS.

REFERENCES orrEn The following references are of record in the file ofthis patent: V

UNITED STATES PATENT Number Name Date 2,206,636 Hunter July 2, 19402,217,170 Hunter Oct. 8, 1940 2,269,267 Hunter Jan. 6, 1942 2,307,180Yngve Jan. 5. 1943 2,319,182 Van der Pyl May 11, 1943 2,572,798

Ayers Oct. 23, 1951

1. MOLDING COMPOSITIONS CAPABLE OF PRODUCING COLD FLOW-RESISTANT MOLDEDPRODUCTS COMPOSED OF A MOLDABLE MASS CONTAINING A RESINOUS MOLDINGMATERIAL HAVING A MODULUS OF ELASTICITY NOT GREATER THAN 6 AND ACOMPRESSIVE STRENGTH NOT GREATER THAN 19,000, SAID MASS NOT HAVING BYITSELT THE PROPERTY OF PRODUCING COLD FLOW-RESISTANT MOLDED PRODUCTS,INCOMBINATION WITH A FINELY DIVIDED LIGNO-CELLULOSE FILLER THE PARTICLESOF WHICH ARE NOT MORE THAN 30 MICRONS IN DIAMETER, AND ABOUT 1 TO 10% OFA STIFFENING AGENT SELECTED FROM THE GROUP CONSISTING OF PRECIPITATEDCALCIUM SILICATE, PRECIPITATED SILICA, ALUMINUM HYDRATE, AND REINFORCINGCLAYS, THE SAID AGENT HAVING A MAXIMUM AVERAGE PARTICLE DIAMETER OF NOTGREATER THAN 5 MICRONS.